6 BULLETIN 036, U. S. DEPARTMENT OE AGBIGTJL.TUEE. 
represent the actual number of birds produced from this marsh that 
are available to sportsmen there and elsewhere. 
HABITS AND ACTIVITIES AFTER THE NESTING SEASON. 
In the course of studies in this region it was learned that the 
great marshes in the delta of Bear River not only offer a favorable 
breeding ground for many pairs of ducks, but also that they are 
even more important as a refuge and feeding ground for a much 
larger number of birds after these are freed from family cares in 
other regions. To maintain themselves in condition, all species of 
birds must renew their bodily covering of feathers at least once 
each year, while many forms molt partially or entirely at shorter 
intervals. This usually is a gradual process, as only a few feathers 
drop out at one time and are replaced by new ones. One or two 
feathers fall in either wing at approximately the same time and 
more are not lost until the first ones are partly grown. By this 
continuous renewal the powers of flight of the ordinary bird are 
not seriously hampered and it is able to feed, fly about, and evade 
its enemies as usual. 
In wild ducks and geese, however, the process is entirely different. 
In common with grebes and rails, the ducks and other anserine birds 
drop all the feathers of the wings and tail at about the same time, 
and for a period of four or five weeks are wholly unable to fly. At 
this time they must have access to large marsh areas where they 
may find an abundance of food without exposing themselves unduly 
to the attacks of enemies. Many thousand ducks from other areas 
gather in the Bear River marshes each season for this purpose, 
greatly augmenting the numbers of those that breed there. 
In all the species of ducks that frequent this area in summer, 
except the ruddy duck, the males nearly always desert their mates as 
soon as the complete set of eggs has been deposited and incubation 
has begun. During three summers spent on Bear River the writer 
saw many hundreds of broods of wild ducks, but. except in the case 
of ruddy ducks, not more than ten instances were observed where 
drakes accompanied the young. The male ruddy duck, like the 
Canada goose, usually stays with the female until the ducklings are 
well grown, and it is common to see one at the head of a brood 
of dusky young, swimming with chest and neck puffed out and tail 
spread. Occasionally a male gadwall, shoveler, or mallard may 
accompany a female and her brood, but such occurrences are rare. 
After the pairing season the drakes begin to join in flocks, and 
large bands of these males gather to feed and rest on the great open 
bay-. At this time they are in bright, showy plumage, but early 
in summer a change takes place. The body feathers are replaced by 
a plain dull plumage more or less resembling that of the female, 
